Novel manipulations of ratio spectra as powerful tools for resolution and quantitative determination of Pyridostigmine bromide and its' related substances; A comparative study

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2019-03, Vol.210, p.66-75
• Main Authors: Abdelaleem, Eglal A., Emam, Aml A., Naguib, Ibrahim A., Abdallah, Fatma F.
• Format: Article
• Language: English
• Subjects: Derivative ratio difference; ICH guidelines; Induced ratio difference; Pyridostigmine bromide; Ratio subtraction ratio difference
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2018.11.011

Resolution and quantitative determination of ternary mixture with severely overlapped spectra without any preliminary separation steps represents a big challenge for any analyst. Smart and novel spectrophotometric methods are continuously innovated for achieving the above mentioned target. Novel applications of ratio difference spectrophotometric technique utilizing ratio spectra and derivative ratio spectra are applied in presented work. The proposed methods included derivative ratio difference (DRD) and ratio subtraction ratio difference (RSRD) methods. Comparative study was achieved between the proposed methods and the recently developed induced ratio difference (IRD) method. The developed methods were assessed through the analysis of ternary mixtures with different ratios of Pyridostigmine bromide (PR) and its related substances; impurity a (IMP A) and impurity b (IMP B). Analysis of PR in a pharmaceutical dosage form without any interference from other inactive ingredients was also a successful application of the proposed methods. As per ICH guidelines, the proposed methods were validated ensuring their accuracy, precision and specificity. Statistical comparison between the developed methods and the reference method was done, where calculated F and t values were less than the theoretical ones in regards to accuracy and precision. [Display omitted] •Novel manipulations of ratio difference spectrophotometric technique are developed in the presented work.•The novel spectrophotometric methods are presented as a comparative study.•The validity of the proposed methods was revealed as per ICH guidelines.•Necessary statistical comparison was done between the proposed methods and the reference one.•The proposed methods can be applied for routine analysis of complex ternary mixtures.